When upgrading or modernizing an electrical power transmission or distribution network, parts of such a network are newly produced or are produced instead of existing devices. Parts of a network such as those include, for example, transmission lines, switchgear assemblies, wattless component compensation devices etc. A network operator and/or a manufacturer of appliances and systems carries out a comprehensive analysis for planning purposes. The aim of the analysis is to define a configuration of appliances and/or systems which can be introduced into the network and satisfies predetermined technical and financial requirements of the network operator. One result of this analysis is a defined configuration, that is to say a planned arrangement of specific appliances from that manufacturer. One problem that arises when defining this configuration is that, firstly, the network operator knows his requirements and has simulation systems by means of which he can test and compare various possible configurations. However, human experts are required to do this, who not only know the simulation systems but also have extensive knowledge about the range of appliances from that manufacturer and about their configuration options. Secondly, the manufacturer has knowledge about his appliances, in particular about simulation models. However, he cannot, or else does not wish to, make these fully available to the network operator. Even if they are available to the network operator, the network operator will nevertheless often determine technically and financially suboptimum configurations, since he is using only solutions that are known by him, without including new products and their new characteristics, and since he cannot have an overview of and assess all the aspects of the appliances and appliance combinations.